Embroidering-machine.



J. J. KNEGHT.

BMBROIDERING MACHINE.

APPLICATION FILED 00120. 1913.

1,120,722, Patented Dec. 15, 1914.

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iinrrnn stares raannr canton JGHANN JACOB KNECHT, OF KAPPEL, NEAR-CHEMNITZ, GERT/IANY, ASSIGNOR TO THE FIRM OF MASCHINENFABR NITZ,GERMANY.

K KAPPEL A. (3., OF 11.

rest, NEAR enem- EMBROIDEEING-1VIAGHINE.

Application filed October 28, 1918.

To all whom it may concern:

Be it known that I, JOI-IANN Jason KM: rrr, a citizen of theConfederation of Switzerland, and resident of .Kappel, ncar Chemnitz, inthe Kingdom of Saxony, Germany, have invented certain new and usefulImprovements in Embroidering- Machines, of which the following is aspecification.

This invention relates to certain improvements in embroidering machinesand more particularly to mechanism for counterbalancing the weight ofthe tambour frame of the type in which the tambour frame is supported bya parallel motion mechanism, comprising a plurality of connected pivotedelbow levers provided with compensating spring mechanism forcounterbalancing the weight of the frame.

The present invention relates to that class of compensating mechanism inwhich not only the varying forces of the counterbalancing springs, asthey are expanded or contracted during the movements of the tambourframe, are automatically compensated, but in which the varying loadmoment due to the Varying leverage of the weight of the tambour frameabout the pivots of the supporting elbow levers is also automaticallycompensated by meanscf a rocking mem er having a correspondingly curvedsurface and a flexible member having rolling contact with the curvedsurface.

According to the present invention the rocking member is constructed inthe form of a cam which rotates in unison with a cylindrical member, thecam being connected to the counter-balancing spring by a flexible memberwhich makes rolling contact with the cam, while the cylindrical memberis connected to one arm of one of the elbow levers constituting theparallel motion mechanism by a second flexible member which makesrolling contact with the cylindrical member.

in order that the intention may be more clearly understood reference ismade to the accompanying drawing illustrating the preferred constructionof my improved counter balancing mechanism in elevation as applied tothe tambour frame of an embroidering machine.

in the drawing 1 indicates the usual movable tambour frame of anembroidering machine which rests on the system of levers, two of whichare shown on the drawing,

Patented Dec. 15, 1914.

Serial No. 796,305.

these levers constituting the usual parallel motion mechanism. Pivotallymounted at 3 on brackets 3 are elbow levers 1, i, the arms a carryingrollers 3 which support the tambour frame, while the arms l areconnected by means of a wire 6. Secured at one end to a stationarysupport 7 is a counterbalancing spring 8, the free end of which isconnccted to a flexible metal band 9 which makes rolling contact withthe curved surface of a rocking member or cam 10 rotatably mounted on ashaft 11 carried in suitable bearings 12. lhe flexible member passesaround the curved surface of the cam 10 and is secured thereto at 13. Itwill thus be seen that the tendency of the spring 8 is torotate the am10 in anti-clockwise direction. Rotating in unison with the cam 10 is acylindrical member or roller 1-1 likewise mounted on the shaft 11, andconnected to the cylindrical member at the point 15 is a flexible metalband 16 connected to an adjusting element 17 adjustably mounted in theend of the arm i of one of the elbow lovers. The weight of the tambourframe 1 will thus tend to rotate the cylindrical member 1i and cam 10 inclockwise direction, this tendency being equalized by the retractingforce of the spring 8 so that the tambour frame 1 is supported by theaction of the spring 8.

1f the tamhour frame is moved upwardly or downwardly from the positionshown on the drawing during the usual operations of the cmbroideringmachine, the arms a of the elbow lovers will follow the movement of thetambour frame and the cam 10 will be correspondingly rotat 2d, while theleverage of the spring 8 about the shaft 11 will vary according to theposition of the cam 10, thus compensating for the variations in theretracting force of the spring 8.

Since the leverage of the weight of the tambour frame 1 about the axis 3of the elbow levers varies according to the position the tainbour frame,it is necessary to construct the curved surface of the cam 10 in such amanner as to also compensate for this variation. For this purpose therequired curvature of the cam may be determined either mathematically orempirically.

I claim z- 1. In an embroidering machine having a movable tambour frame,a counterbalancing mechanism therefor comprising a plurality of elboWlevers, one arm of each lever supporting said frame and the other armsof said levers being connected together, a rotatable cylindrical member,a flexible member connecting one of the connected arms of said levers tosaid cylindrical member and adapted to make rolling contact With thelatter, a rocking member rotating in unison With said cylindrical memberand having a curved surface, a counterbalanoing spring fixed at one endand a flexible member connecting the free end of said spring with saidrocking member and adapted to make rolling contact With the curvedsurface thereof, the form of said curved surface being such that boththe varying load moment of the frame and the varying forces of thespring are compensated.

2. In an embroidering machine having a movable tambour frame, acounterbalancing mechanism therefor comprising a plurality of elbowlevers, one arm of each lever supporting said tambour frame and theother arms of said levers being connected together, a rotatable roller,a flexible band connected at one end to and passed around'said rollerand connected at its other end to one arm of.

the connected arms of said levers, a rocking .member rotating in unisonwith said roller and having a curved surface, a counterbalancing springfixed at one end and a flexible member connecting the free end of saidspringvvith said rocking member and adaptedto make rolling contact Withthe curved surface thereof, the form of said curved surface being su hthat both the varying load moment of the frame andthe varying forces ofthe spring are compensated.

3. In an embroidering machine having a movable tambour frame, acounterbalancing mechanism therefor comprising a plurality of elbowlevers, one arm of each lever supporting said frame and the other armsof said levers being connected together, a rotatable cylindrical member,a flexible member connecting one of the connected arms of said levers tosaid cylindrical member and adapted to make rolling conta t with thelatter, a curved cam rotating in unison With said cylindrical member, acounterbalancing spring fixed at one end and a flexible band connectedat one end to the free end of said spring and passed at its other endaround said curved cam and secured thereto, the form of said curvedsurface being such that both the varying load moment of the frame andthe varying forces of the spring are compensated.

In testimony whereof I have affixed my signature in presence of twoWitnesses.

JOHANN JACOB KNEOHT.

' Witnesses:

Ennns'r J. lilAenN, Hans MnIoKn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, .Washington, 1?. G.

